Silicon bronze, Frearson (Reed & Prince), oval head, wood screws. A superior material for underwater fastenings.• A tapered shank screw for use exclusively in wood; the smooth shaft under the head allows gap-free tightening of the outer piece against the inner piece• Oval head screws are similar to flat head, but have a slightly rounded top for a more finished look• Length is measured from the rim of the head to the end of the fastener